1. Field of the Invention
This invention relates generally to boat anchors and more particularly to boat anchors which include a feature to permit the anchor to be released from underwater entanglements in the event normal anchor retrieval is not possible.
2. Description of the Prior Art
It has been known for many years that boat anchors can become entangled in underwater obstructions such as rocks, coral reefs, etc. Retrievel of the anchor once it has become entangled is time consuming and there is a substantial probability that the anchor may be lost. It is also known in the prior art that anchors can be designed with a release feature which can be operated at the discretion of the boat operator. If the owner determines that retrieval in the normal manner is not possible, the operator uses the release feature to disengage the flukes from whatever obstruction is encountered. It is also known in the prior art that anchor chains can become entangled in underwater obstructions and it has been suggested that a float on the water surface be provided to keep the chain in a vertical position. A brief summary of pertinent prior art patents illustrating the foregoing will now be provided.
Wixon, in his 1889 U.S. Pat. No. 411,948 entitled "Anchor", describes a device having a pair of sharp, pointed flukes pivoted to an anchor shaft. Each fluke includes a spur portion which is generally parallel to the shaft when the anchor is in its functional position. A ring is slidedly disposed over the shaft and is designed to encircle the spurs to retain the anchor in its normal position. A separate rope is attached to the ring and if the boat owner desires to release the anchor, he pulls the ring upwardly to release the spurs and allow the flukes to drop to a position in which they point downwardly from the shaft.
In Andrews' U.S. Pat. No. 2,674,970 issued Apr. 13, 1954 and entitled "Boat Anchor", the anchor includes three flukes having heart-shaped end points, the flukes being pivotally coupled to the shaft by thin rods. The inner ends of the flukes are recessed into the shaft and a spring-loaded collar slips over the inner ends when the anchor is in its functioning position. By pulling a separate rope, the operator can retract the collar against the spring pressure, allowing the flukes to drop downwardly into a retrieval position.
Bartels, et al. describe a "Collapsible Boat Anchor" in their U.S. Pat. No. 2,940,411 issued June 14, 1960. The anchor includes four thin, ski-shaped flukes pivoted to a bottom plate. Each fluke is also coupled to the shaft by a tie rod. A first end of the tie rod is pivoted to the fluke outwardly from the shaft and the other end of the tie rod is slidably coupled to the shaft through a slot. A ring is coupled to the bottom of the anchor and the anchor rope is attached to this ring. A snatch clip is positioned high on the shaft and the rope passes through the snatch clip before rising to the surface. When underwater obstructions are encountered, the operator jerks the rope to release it from the snatch clip and the anchor is raised from the bottom allowing the flukes to drop downwardly into a retrieval position.
Another prior art device is described in Triechman's U.S. Pat. No. 2,982,244 issued May 2, 1961 for "Collapsible Boat Anchor." This anchor includes four pointed, elongate flukes, each with a notch on the pivoted end. The flukes are held in the functioning position when a locking ring engages the notches. A sliding collar weight is provided to lower the locking ring and allows the flukes to drop into a retrieval position.
Swails, in U.S. Pat. No. 3,021,812 issued Feb. 20, 1962 for "Releasable Anchor" describes a system similar to that of the aforementioned Andrews patent, but this device includes a spring-loaded pin trigger mechanism for releasing the locking collar. The collar is biased toward the release position. Once the pin is released, the flukes drop downwardly for retrieval.
Wheeler, in U.S. Pat No. 3,059,607 issued Oct. 23, 1962 for "Anchor" describes a device which includes elongate, pointed flukes pivotally coupled to a shaft at one end with tie rods slidably coupled to the shaft and movable downwardly thereon to permit the flukes to drop to a retrieval position.
A different arrangement is depicted in Jensen's U.S. Pat. No. 3,123,037 issued Mar. 3, 1964 for "Boat Anchor." In this device, the spring-loading is accomplished below the flukes on an extension of the shaft and the spring urges the flukes to a downward retrieval position. The flukes are pivotally coupled to a first collar. A second collar is secured to the upper end of the shaft and a tie rod is coupled between each fluke and the second collar. A release pin mechanism and second rope are provided for disengaging the pin and placing the anchor in the retrieval position.
Botine's June 23, 1964 U.S. Pat. No. 3,138,134 for a "Boat Anchor" describes another spring-loaded system which includes a plunger and a spring. The bottom of the plunger engages the inner ends of the elongate flukes until sufficient pressure is applied against the spring to cause the anchor to assume its retrieval position.
In U.S. Pat. No. 3,397,665 issued Aug. 20, 1968 for "Boat Anchor", Lindly describes another system employing pivotable flukes and a sliding casing which locks the flukes in the anchoring position. The anchor rope is attached to the casing while a weaker section of the rope is attached to the anchor body. If normal tension is applied to the weaker section, it will hold and the anchor can be raised. If the anchor becomes entangled, greater tension will brake the weak section of the rope allowing the casing to release so the anchor assumes its retrieval position.
Guier, in U.S. Pat. No. 3,450,008 issued June 17, 1969 for "Anchor Having Pivotable Flukes", describes an anchor having a fluke portion formed from pre-cut plates which have holes in them. Rods pass through the holes and are journaled to retain the plates in assembly. A float is also provided which has fins on it. The fins rotate when the anchor is being lowered to act as a drag on anchor descent.
An "Anchor Float Adapter" is described by Sabella in his Jan. 10, 1978 U.S. Pat. No. 4,067,287. The adapter includes a tubular body suspended from a float, the body having quick connect and disconnect features.
All of the aforementioned devices suffer from one or more disadvantages. Many of the devices are unsuitable for use in salt water because of the corrosive effect on parts such as springs, release pins, and the like. Other devices are cumbersome and require time consuming manipulation of two ropes. In addition, most of the devices which employ a quick release feature have sharp, elongate flukes which are not effective when anchoring in sand. An anchor system which overcomes the above-noted disadvantages would be a significant advance in the anchor art.